How do I detect which SKSpriteNode has been touched

I find a similar question, but I am trying to detect and identify which Sprite the user touch, and I don't know how to do that. This is my variable:

var sprites: [[SKSpriteNode]] = [[SKSpriteNode(imageNamed: "a"), SKSpriteNode(imageNamed: "b")], [SKSpriteNode(imageNamed: "c"),SKSpriteNode(imageNamed: "d")]]

The idea is identify the spriteNode and then replace it for other sprite or change the color, but I don´t know how to do it with this matrix of spriteNodes, I guess the first step it´s identify the sprite.

What you are trying to do (even if I don't see a reason for this) can be accomplished using delegation pattern. Basically, you will tell your delegate (the scene, or whatever you set as a delegate) to do something for you, and you will do that directly from within the button's touchesBegan method. Also, you will pass the button's name to a scene.

To make this happen, first you have to define a protocol called ButtonDelegate. That protocol defines a requirement which states that any conforming class has to implement a method called printButtonsName(_:):

protocol ButtonDelegate:class {

   func printButtonsName(name:String?)
}

This is the method which will be implemented in your GameSceneclass, but called from within button's touchesBegan. Also, this method will be used to pass a button's name to its delegate (scene), so you will always know which button is tapped.

Next thing is button class itself. Button might look like this:

class Button : SKSpriteNode{

    weak var delegate:ButtonDelegate?

    init(name:String){
        super.init(texture: nil, color: .purpleColor(), size: CGSize(width: 50, height: 50))
        self.name = name
        self.userInteractionEnabled = true
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }


    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {

        delegate?.printButtonsName(self.name)
    }  
}

The important thing here is userInteractionEnabled = true, which means that button will accept touches. Another important thing is a delegate property. As already mentioned, buttons will have the scene set as their delegate. Setting a scene as delegate of buttons will be done later when we create some buttons... To make this easier for you, think of a delegate as a worker who works for his boss :) The boss (a button) tells his worker (a scene) to do something for him (to prints his name).

Okay, so lets make sure that scene conforms to a ButtonDelegate protocol...Why is this important? It is important because the worker (scene) must follow the orders of his boss (a button). By conforming to this protocol, the worker is making a contract with his boss where confirming that he knows how to do his job and will follow his orders :)

class GameScene: SKScene, ButtonDelegate {


    override func didMoveToView(view: SKView) {

        let play = Button(name:"play")
        play.delegate = self
        let stop = Button(name:"stop")
        stop.delegate = self

        play.position = CGPoint(x: frame.midX - 50.0, y: frame.midY)
        stop.position = CGPoint(x: frame.midX + 50.0, y: frame.midY)

        addChild(play)
        addChild(stop)
    }

    func printButtonsName(name: String?) {

        if let buttonName = name {
            print("Pressed button : \(buttonName) ")
        }

        //Use switch here to take appropriate actions based on button's name (if you like)
    }
}

And that's it. When you tap the play button, the touchesBegan on a button itself will be called, then the button will tell its delegate to print its name using the method defined inside of scene class.

First, you need another way to create the sprite, here are a way:

let spriteA = SKSpriteNode(imageNamed: "a")
scene.addChild(spriteA)
let spriteB = SKSPriteNode(imageNamed: "b")
scene.addChild(spriteB)
...and so on...

Now we needs to set a name for the sprite so we can know which node is tapped later. To add a name for a sprite just do this:

spriteNode.name = "name of the sprite"

Putting this code in the above example will look something like this:

let spriteA = SKSpriteNode(imageNamed: "a")
spriteA.name = "a"
scene.addChild(spriteA)
let spriteB = SKSPriteNode(imageNamed: "b")
spriteB.name = "b"
scene.addChild(spriteB)
...and so on...

To detect touches put this into your SKScene subclass:

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    let touch = touches.first as UITouch!
    let touchLocation = touch.locationInNode(self)
    let targetNode = nodeAtPoint(touchLocation) as! SKSpriteNode
}

The targetNode is the node you tapped.

If you wants to get the name of the sprite you can use targetNode.name.